1. Field of the Invention
This invention relates to an interfacing circuit and more particularly to an electronic sample and hold circuit for providing an output analog voltage representative of the peak magnitude of a sampled input signal.
2. Description of the Prior Art
Sample and hold circuits can be employed in many applications where an interfacing between a particular type of signal to a representative analog voltage is required. For instance, it may be desired to sample a time varying signal generated by a particular system to provide a signal proportional thereto for utilization in adjusting a particular parameter of the system in a closed loop manner.
One example of an application in which a sample and hold circuit may be useful is a fuel metering system for controlling the fuel/air mixture ratio in accordance with the rotational speed of an internal combustion engine. The engine can generate a time varying signal which is utilized to provide a signal having a peak amplitude proportional to the rotational speed of the engine. By sampling this signal an analog voltage can be provided which in turn can be used to control the fuel/air mixture ratio. Thus, a correct mixture ratio can be supplied for more efficiently controlling the operation of the engine.
Thus, it is an object of the present invention to provide an improved sample and hold circuit suitable for fabrication in monolithic integrated circuit form.